When I winterize, I don't open the low point drains until last. I put the hose in the "pink stuff" gallon jug and turn the water pump on. There is already water in the lines, not drained yet. The pink stuff pushes out the clear water. I open low point drains last, after pumping the pink, and drain the pink out.
I have found the hose has to be in the gallon jug before turning on the water pump. If the pump is turned on first, then the hose is put in the pink stuff container, the water pump will never pull. The end of the hose has to be submerged before turning the water pump on.
I leave all the faucets turned off. The pink stuff will reach pressure quickly and then shut off. I then go to each faucet and turn it on just enough to get the pink stuff flowing freely. When the faucets begin to spit air, the jug is getting empty. I turn the water pump off, then switch to a new gallon jug, then turn the pump on again. I don't know why it has to work this way, but it does. Hose in jug or bucket first, create the vacuum, then turn the pump on.
See if that helps. Chances are, you are turning the pump on first then trying to get the hose in the pink. Won't work that way. Been there ... done that.!! Learned the hard way.